ABRICATION AND MODIFICATION OF SCREEN-PRINTED CARBON ELECTRODE (SPCE) USING CARBON NANOTUBES AS AN ELECTROCHEMICAL BIOSENSOR APPLICATION FOR DOPAMIN DETECTION

• Main Author: Rasyid A, Ahmad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/50029
• Institution: Institut Teknologi Bandung

Normal levels of dopamine compounds in the blood are in the range 0 – 0,25 nM. Then, normal levels of dopamine compounds in the urine range from 0.3 - 3 ?M. Too little or too much dopamine can be harmful to the body and has been linked to a variety of mental and medical conditions. Someone who has excess dopamine can experience mental-related disorders, such as schizophrenia and bipolar disorder. Therefore, it is necessary to measure dopamine levels regularly so that the dopamine content in the body can be maintained under normal conditions and avoid several dangerous diseases. Some of the commonly used methods of measuring dopamine compounds are colorimetric, enzymatic, and electrochemical. The electrochemical method was chosen because it can measure dopamine compounds with high sensitivity and low production costs. One application of the electrochemical method that will be used is the ScreenPrinted Carbon Electrode (SPCE). SPCE is a technology that utilizes carbon-based electrodes which are widely used for the development of electrochemical sensors. However, because the carbon-based electrodes are not selective, modifications are needed to increase the electrode selectivity and sensitivity to dopamine. One of the materials that can be used to increase the sensitivity and selectivity of SPCE is Carbon Nanotube (CNT). CNTs were chosen because they are very stable and strong, have good conductivity, large surface area, and small dimensions. In this study, the SPCE modification was carried out using the drop-casting method. Materials modified on the surface of the SPCE work electrode include FMWCNT (with and without nafion), MWCNT / AgNP, and MWCNT-DMF. From CV and DPV testing on dopamine, showed that FMWCNT (with nafion), MWCNT / AgNP and MWCNT-DMF had a sensitivity of 5.69x10-5, 3.90x10-5, and 1.16x10-5 A mM-1 cm- 2, the detection limit is 0.30, 0.22, and 0.0081 ?M, the quantification limit is 1.01, 0.75, and 0.027 ?M, and with an average measurement error of 0.29%, 0.53 %, and 19.65%. CNT has good selectivity in recognizing dopamine compounds when compared to other compounds present in urine, such as glucose and urea. From the various tests that have been carried out, SPCE has been made and modified with CNT which can be applied as an electrochemical biosensor for dopamine with good sensitivity and selectivity. Finally, a comparison test was carried out using commercial SPCE (Zimmer & Peacock) modified with MWCNT / AgNP to be compared with homemade SPCE.